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=====Connection Trouble=====

=== Options > Connections "Show NMEA Debug Window" is Modal === 

 Linux & MacOS Issue: Check display of the "NMEA Debug Window" and the "Connection window" simultaneously causes "Pause" and "Copy" to be are inactive. The connection window has to be closed first, then Pause works.

The Options window, in which the Connections are displayed, is what is called a modal window. Everything else is blocked until that window is closed. Modal windows make for simpler programming, which is why they are used.

For examining NMEA sentences, you could consider the [[https://github.com/antipole2/JavaScripts-shared/blob/main/MessageNMEAsampling/MessageNMEAsampling.adoc|MessageNMEAsampling script]] for the [[https://opencpn-manuals.github.io/main/javascript/index.html|JavaScript plugin]]. It samples NMEA for a period and then reports what sentences have been seen together with their counts and then prints one sample of each. You can also configure it to display all of the sentences you are interested in. This is much easier than trying to tame the rush of sentences in the debug window.


=== Can OpenCPN receive multiple data streams from a USB hub? ===

  * Yes. Simple Setup. The USB Hub with the device drivers creates a separate Virtual COM port for each USB at the required speed. OpenCPN then acts as the Multiplexer when you make separate Connections for each of the virtual COM ports created. Example:
  * Inateck USB3.0 3-port hub with gigabit ethernet port $20
  * [[:opencpn:supplementary_hardware:gps_devices|Bu-353-S4 GPS puck]] $25
  * [[:opencpn:supplementary_hardware:ais_devices#daisy_ais_receivers|dAISy AIS Receiver]] $70
  * [[:opencpn:supplementary_hardware:seatalk_nmea|Tiny Seatalk Link]] $150 for Raymarine Instruments (up to ST60).
  * Label the ports for the devices and use those ports or you'll be redoing OpenCPN "Connections".
  * Install each device's drivers.
  * or another example, Vesper AIS and RS422 NEMA instruments.
  * For more about [[:opencpn:supplementary_hardware|]] or consult with a marine electronics service.
  * A multiplexer will join multiple sources into a single output to OpenCPN. Multiplexers come in a great variety, to do many different jobs, read the specs.
  * Tips for working with multiple serial sources
      * Label the hub and usb devices and always plug them into the same location once they work in Opencpn.
      * OCPN will never assign a port to a new connection by itself, you must select one from the dropdown list OR enter it yourself, for example: "COM11".
      * To confirm which COM port is used for a USB device, open Windows //Device Manager//  and watch what happens when the device is connected and disconnected from the USB-HUB/Splitter.
      * Then select or enter the corresponding COM port in OCPN Connections.
      * Be sure to set correct baud rate.
      * To find and use the Device Manager look [[:opencpn:opencpn_user_manual:getting_started:gps_setup#method_1a_dedicated_gps_receiver_driver|here]]

=== In Options > Connections > Fransom GPSGATE virtual com port not seen. ===

  * Simply fill in the virtual port name manually, the field is not limited to selection of the ports that were detected.

=== In Connections > NMEA Data Window can an atypical message type be filtered? ===

  * You can add absolutely anything to the filter (Click on the "Add" button), the predefined list is there just to save you some typing for the most common message types.

=== Serial interface for NMEA0183 input -AIS data & navigation instruments- switch without reason ===

  - Raspbian OS, [[https://github.com/OpenCPN/OpenCPN/issues/1928|https://github.com/OpenCPN/OpenCPN/issues/1928]]
  - This is an OS problem. your OS starts numbering with the first device coming up, and this is not always happen in the same sequence. The good news is you can tell your OS to give an fixed name to a fixed device, and you can use this fixed name in OpenCPN. see:
  - [[https://www.domoticz.com/wiki/Assign_fixed_device_name_to_USB_port|https://www.domoticz.com/wiki/Assign_fixed_device_name_to_USB_port]]
  - [[https://www.domoticz.com/wiki/PersistentUSBDevices|https://www.domoticz.com/wiki/PersistentUSBDevices]]
  - Or use Openplotter and its "serial" for the same purpose :)

=== Flatpak Data port connection issues? ===

See [[https://www.cruisersforum.com/forums/f134/dataport-connection-problems-o-v5-6-0-a-259859.html#post3564692|CF Dataport Connection problem]] There are some things related to serial data ports, in particular on Flatpak. * There is a bug: [[https://github.com/OpenCPN/OpenCPN/issues/2528|https://github.com/OpenCPN/OpenCPN/issues/2528]]- * The port must be accessible. See [[https://github.com/OpenCPN/OpenCPN/blob/master/LINUX_DEVICES.md|https://github.com/OpenCPN/OpenCPN/blob/master/LINUX_DEVICES.md]], the chapter on Device Access. * Even if the port is accessible it might not be visible in the UI. Two solutions. * The first is to write the name of the device, perhaps something like /dev/ttyUSB0 in the GUI (one don't have to select from the drop-down list, it's possible to enter the device name as well) * The second is to create a device link as described in [[https://github.com/OpenCPN/OpenCPN/blob/master/LINUX_DEVICES.md|https://github.com/OpenCPN/OpenCPN/blob/master/LINUX_DEVICES.md]], the chapter on Fixed Device Names. Such links are visible in the GUI

A new point Flatpak point fix has been pushed for this issue. To update the Flatpak [[https://www.cruisersforum.com/forums/tags/installation.html|installation]] do

Code:

<alt2> $ flatpak update org.openpcn.OpenCPN </alt2>

Note that despite the patch, devices must still be accessible as described in [[https://github.com/OpenCPN/OpenCPN/blob/master/LINUX_DEVICES.md|https://github.com/OpenCPN/OpenCPN/b...NUX_DEVICES.md]]

=== Why doesn't OpenCPN recognize "localhost" as a source? ===

On Rpi I type Telnet localhost 10110 I see the stream of NMEA 0183 sentences coming from the Signalk Server. Apparently OpenCpn does not work that way.

OpenCPN does not recognize anything other than Q4 notation in the address field. "localhost" is a semi-standard shorthand notation, used on many systems and apps. In OpenCPN, Instead of "localhost", use ip of 127.0.0.1. It is the same thing.

=== Function 'Filter NMEA/Course and Speed data' not honored if input thru Signal K ===

[[https://github.com/OpenCPN/OpenCPN/issues/2292|See #2292]] If an NMEA 2000 GPS is connected and Signal K is used to read NMEA 2000 into OpenCPN the data will not honor the filter settings for NMEA/Course and Speed data. The course predictor will jump both in length and direction, not damped by the filter setting.

I can find also SOG/COG from SignalK data stream is passing the filter function. (by PostProcessNMEA()) But the filter function is by-passed if "Calculate SOG and COG from position changes" is enabled in Options→Ships→Own ship. Pls check. I was falling into that trap myself.

=== How exactly does NMEA 0183 HDG Sentence work? ===

If HDG message also contains the variation and E/W flags then O will use that. If not then it will look in RMC message for a variation. If nothing there it will use WMM plugin unless user has selected the variation manually in options.




